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Diffstat (limited to 'arch/tile/mm/highmem.c')
| -rw-r--r-- | arch/tile/mm/highmem.c | 277 |
1 files changed, 0 insertions, 277 deletions
diff --git a/arch/tile/mm/highmem.c b/arch/tile/mm/highmem.c deleted file mode 100644 index eca28551b22d..000000000000 --- a/arch/tile/mm/highmem.c +++ /dev/null @@ -1,277 +0,0 @@ -/* - * Copyright 2010 Tilera Corporation. All Rights Reserved. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation, version 2. - * - * This program is distributed in the hope that it will be useful, but - * WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or - * NON INFRINGEMENT. See the GNU General Public License for - * more details. - */ - -#include <linux/highmem.h> -#include <linux/module.h> -#include <linux/pagemap.h> -#include <asm/homecache.h> - -#define kmap_get_pte(vaddr) \ - pte_offset_kernel(pmd_offset(pud_offset(pgd_offset_k(vaddr), (vaddr)),\ - (vaddr)), (vaddr)) - - -void *kmap(struct page *page) -{ - void *kva; - unsigned long flags; - pte_t *ptep; - - might_sleep(); - if (!PageHighMem(page)) - return page_address(page); - kva = kmap_high(page); - - /* - * Rewrite the PTE under the lock. This ensures that the page - * is not currently migrating. - */ - ptep = kmap_get_pte((unsigned long)kva); - flags = homecache_kpte_lock(); - set_pte_at(&init_mm, kva, ptep, mk_pte(page, page_to_kpgprot(page))); - homecache_kpte_unlock(flags); - - return kva; -} -EXPORT_SYMBOL(kmap); - -void kunmap(struct page *page) -{ - if (in_interrupt()) - BUG(); - if (!PageHighMem(page)) - return; - kunmap_high(page); -} -EXPORT_SYMBOL(kunmap); - -/* - * Describe a single atomic mapping of a page on a given cpu at a - * given address, and allow it to be linked into a list. - */ -struct atomic_mapped_page { - struct list_head list; - struct page *page; - int cpu; - unsigned long va; -}; - -static spinlock_t amp_lock = __SPIN_LOCK_UNLOCKED(&_lock); -static struct list_head amp_list = LIST_HEAD_INIT(amp_list); - -/* - * Combining this structure with a per-cpu declaration lets us give - * each cpu an atomic_mapped_page structure per type. - */ -struct kmap_amps { - struct atomic_mapped_page per_type[KM_TYPE_NR]; -}; -static DEFINE_PER_CPU(struct kmap_amps, amps); - -/* - * Add a page and va, on this cpu, to the list of kmap_atomic pages, - * and write the new pte to memory. Writing the new PTE under the - * lock guarantees that it is either on the list before migration starts - * (if we won the race), or set_pte() sets the migrating bit in the PTE - * (if we lost the race). And doing it under the lock guarantees - * that when kmap_atomic_fix_one_pte() comes along, it finds a valid - * PTE in memory, iff the mapping is still on the amp_list. - * - * Finally, doing it under the lock lets us safely examine the page - * to see if it is immutable or not, for the generic kmap_atomic() case. - * If we examine it earlier we are exposed to a race where it looks - * writable earlier, but becomes immutable before we write the PTE. - */ -static void kmap_atomic_register(struct page *page, int type, - unsigned long va, pte_t *ptep, pte_t pteval) -{ - unsigned long flags; - struct atomic_mapped_page *amp; - - flags = homecache_kpte_lock(); - spin_lock(&_lock); - - /* With interrupts disabled, now fill in the per-cpu info. */ - amp = this_cpu_ptr(&s.per_type[type]); - amp->page = page; - amp->cpu = smp_processor_id(); - amp->va = va; - - /* For generic kmap_atomic(), choose the PTE writability now. */ - if (!pte_read(pteval)) - pteval = mk_pte(page, page_to_kpgprot(page)); - - list_add(&->list, &_list); - set_pte(ptep, pteval); - - spin_unlock(&_lock); - homecache_kpte_unlock(flags); -} - -/* - * Remove a page and va, on this cpu, from the list of kmap_atomic pages. - * Linear-time search, but we count on the lists being short. - * We don't need to adjust the PTE under the lock (as opposed to the - * kmap_atomic_register() case), since we're just unconditionally - * zeroing the PTE after it's off the list. - */ -static void kmap_atomic_unregister(struct page *page, unsigned long va) -{ - unsigned long flags; - struct atomic_mapped_page *amp; - int cpu = smp_processor_id(); - spin_lock_irqsave(&_lock, flags); - list_for_each_entry(amp, &_list, list) { - if (amp->page == page && amp->cpu == cpu && amp->va == va) - break; - } - BUG_ON(&->list == &_list); - list_del(&->list); - spin_unlock_irqrestore(&_lock, flags); -} - -/* Helper routine for kmap_atomic_fix_kpte(), below. */ -static void kmap_atomic_fix_one_kpte(struct atomic_mapped_page *amp, - int finished) -{ - pte_t *ptep = kmap_get_pte(amp->va); - if (!finished) { - set_pte(ptep, pte_mkmigrate(*ptep)); - flush_remote(0, 0, NULL, amp->va, PAGE_SIZE, PAGE_SIZE, - cpumask_of(amp->cpu), NULL, 0); - } else { - /* - * Rewrite a default kernel PTE for this page. - * We rely on the fact that set_pte() writes the - * present+migrating bits last. - */ - pte_t pte = mk_pte(amp->page, page_to_kpgprot(amp->page)); - set_pte(ptep, pte); - } -} - -/* - * This routine is a helper function for homecache_fix_kpte(); see - * its comments for more information on the "finished" argument here. - * - * Note that we hold the lock while doing the remote flushes, which - * will stall any unrelated cpus trying to do kmap_atomic operations. - * We could just update the PTEs under the lock, and save away copies - * of the structs (or just the va+cpu), then flush them after we - * release the lock, but it seems easier just to do it all under the lock. - */ -void kmap_atomic_fix_kpte(struct page *page, int finished) -{ - struct atomic_mapped_page *amp; - unsigned long flags; - spin_lock_irqsave(&_lock, flags); - list_for_each_entry(amp, &_list, list) { - if (amp->page == page) - kmap_atomic_fix_one_kpte(amp, finished); - } - spin_unlock_irqrestore(&_lock, flags); -} - -/* - * kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap - * because the kmap code must perform a global TLB invalidation when - * the kmap pool wraps. - * - * Note that they may be slower than on x86 (etc.) because unlike on - * those platforms, we do have to take a global lock to map and unmap - * pages on Tile (see above). - * - * When holding an atomic kmap is is not legal to sleep, so atomic - * kmaps are appropriate for short, tight code paths only. - */ -void *kmap_atomic_prot(struct page *page, pgprot_t prot) -{ - unsigned long vaddr; - int idx, type; - pte_t *pte; - - preempt_disable(); - pagefault_disable(); - - /* Avoid icache flushes by disallowing atomic executable mappings. */ - BUG_ON(pte_exec(prot)); - - if (!PageHighMem(page)) - return page_address(page); - - type = kmap_atomic_idx_push(); - idx = type + KM_TYPE_NR*smp_processor_id(); - vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx); - pte = kmap_get_pte(vaddr); - BUG_ON(!pte_none(*pte)); - - /* Register that this page is mapped atomically on this cpu. */ - kmap_atomic_register(page, type, vaddr, pte, mk_pte(page, prot)); - - return (void *)vaddr; -} -EXPORT_SYMBOL(kmap_atomic_prot); - -void *kmap_atomic(struct page *page) -{ - /* PAGE_NONE is a magic value that tells us to check immutability. */ - return kmap_atomic_prot(page, PAGE_NONE); -} -EXPORT_SYMBOL(kmap_atomic); - -void __kunmap_atomic(void *kvaddr) -{ - unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; - - if (vaddr >= __fix_to_virt(FIX_KMAP_END) && - vaddr <= __fix_to_virt(FIX_KMAP_BEGIN)) { - pte_t *pte = kmap_get_pte(vaddr); - pte_t pteval = *pte; - int idx, type; - - type = kmap_atomic_idx(); - idx = type + KM_TYPE_NR*smp_processor_id(); - - /* - * Force other mappings to Oops if they try to access this pte - * without first remapping it. Keeping stale mappings around - * is a bad idea. - */ - BUG_ON(!pte_present(pteval) && !pte_migrating(pteval)); - kmap_atomic_unregister(pte_page(pteval), vaddr); - kpte_clear_flush(pte, vaddr); - kmap_atomic_idx_pop(); - } else { - /* Must be a lowmem page */ - BUG_ON(vaddr < PAGE_OFFSET); - BUG_ON(vaddr >= (unsigned long)high_memory); - } - - pagefault_enable(); - preempt_enable(); -} -EXPORT_SYMBOL(__kunmap_atomic); - -/* - * This API is supposed to allow us to map memory without a "struct page". - * Currently we don't support this, though this may change in the future. - */ -void *kmap_atomic_pfn(unsigned long pfn) -{ - return kmap_atomic(pfn_to_page(pfn)); -} -void *kmap_atomic_prot_pfn(unsigned long pfn, pgprot_t prot) -{ - return kmap_atomic_prot(pfn_to_page(pfn), prot); -} |